Radio Resource Management in OFDMA Networks

Radio Resource Management in OFDMA Networks 1 Introduction The convenience and popularity of wireless technology has now extended into multimedia communications, where it poses a unique challenge for transmitting high rate voice, image, and data signals simultaneously, synchronously, and virtually error-free. That challenge is currently being met through Orthogonal Frequency Division Multiplexing (OFDM), an interface protocol that divides incoming data streams into sub-streams with overlapping frequencies that can then be transmitted in parallel over orthogonal subcarriers [2,3]. To allow multiple accesses in OFDM , Orthogonal Frequency Division Multiple Access (OFDMA) was introduced. Relaying techniques, along with OFDMA, are used to achieve high data rate and high spectral efficiency. 1.1 Orthogonal Frequency Division Multiple Access OFDMA, an interface protocol combining features of OFDM and frequency division multiple access (FDMA)., was developed to move OFDM technology from a fixed-access wireless system to a true cellular system with mobility with same underlying technology, but more flexibility was defined in the operation of the system [1,8]. In OFDMA, subcarriers are grouped into larger units, referred to as sub-channels, and these sub-channels are further grouped into bursts which can be allocated to wireless users [4]. 1.2 Relay-Enhanced Networks In cellular systems, a way to achieve remarkable increase in data rate, but without claiming for more bandwidth, is to shrink cell sizes, however, with smaller cells more base stations (BSs) are needed to cover a same area due to which deployment and networking of new BSs acquire significant costs [5]. An alternative solution to this problem is to deploy smart relay stations (RSs), which can communication with each other and with BSs through wireless connections reducing systems cost. A relay station (RS), also called repeater or multi-hop station, is a radio system that helps to improve coverage and capacity of a base station (BS) and the resulting networks employing relay stations are sometimes called cooperative networks [6]. 1.3 Technological Requirement The continuously evolving wireless multimedia services push the telecommunication industries to set a very high data rate requirement for next generation mobile communication systems. As spectrum resource becomes very scarce and expensive, how to utilize this resource wisely to fulfil high quality user experiences is a very challenging research topic. Orthogonal frequency-division multiple access (OFDMA)-based RRM schemes together with relaying techniques allocate different portions of radio resources to different users in both the frequency and time domains and offers a promising technology for providing ubiquitous high-data-rate coverage with comparatively low cost than deploying multiple base stations [5]. Although wireless services are the demand of future due to their mobility and low cost infrastructure but along with this they suffer serious channel impairments. In particular, the channel suffers from frequency selective fading and distance dependent fading (i.e., large-scale fading) [1, 8]. While frequency selective fading results in inter-symbol-interference (ISI), large-scale fading attenuates the transmitted signal below a level at which it can be correctly decoded. Orthogonal Frequency-Division Multiple Access (OFDMA) relay-enhanced cellular network, the integration of multi-hop relaying with OFDMA infrastructure, has become one of the most promising solutions for next-generation wireless communications. 1.3.1 Frequency Selective Fading In wireless communications, the transmitted signal is typically reaching the receiver through multiple propagation paths (reflections from buildings, etc.), each having a different relative delay and amplitude. This is called multipath propagation and causes different parts of the transmitted signal spectrum to be attenuated differently, which is known as frequency-selective fading. In addition to this, due to the mobility of transmitter and/or receiver or some other time-varying characteristics of the transmission environment, the principal characteristics of the wireless channel change in time which results in time-varying fading of the received signal [9]. 1.3.2 Large Scale Fading Large scale fading is explained by the gradual loss of received signal power (since it propagates in all directions) with transmitter-receiver (T-R) separation distance. These phenomenonss cause attenuation in the signal and decrease in its power. To overcome this we use diversity and multi-hop relaying. 1.3.3 Diversity Diversity refers to a method for improving the reliability of a message signal by using two or morecommunication channelswith different characteristics. Diversity plays an important role in combatingfadingandco-channel interferenceand avoidingerror bursts. It is based on the fact that individual channels experience different levels of fading and interference. Multiple versions of the same signal may be transmitted and/or received and combined in the receiver [10]. 1.4 Proposed Simulation Model We developed a simulation model in which each user-pair is allocated dynamically a pair of relay and subcarrier in order to maximize its achievable sum-rate while satisfying the minimum rate requirement. The algorithm and the results of the simulation model are given in chapter 4. 1.5 Objectives The objective of our project is to have a detail overview of the literature regarding Orthogonal Frequency Division Multiple Access (OFDMA), Radio Resource Management (RRM) and Relaying techniques. After literature review we developed a simulation framework in which we will try to use minimum resources to get maximum throughput by using dynamic resource allocation. 1.6 Tools For the design and implementation of proposed Algorithm, we have used the following tools MATLAB Smart Draw Corel Draw 1.7 Overview Chapter 2 contains the literature review. It explains the basic principles of OFDMA, Radio Resource Management (RRM) and the relaying techniques. Chapter 3 explains the implementation of OFDM generation and reception that how an OFDM signal is generated and transmitted through the channel and how it is recovered at the receiver. Chapter 4 could be considered as the main part of thesis. It focuses on the simulation framework and the code. We have followed the paper â€Å"Subcarrier Allocation for multiuser two-way OFDMA Relay networks with Fairness Constraints†. In this section we have tried to implement the Dynamic Resource Allocation algorithm in order to achieve the maximum sum rate. Results are also discussed at the end of the end of the chapter. 2 Literature Review Introduction: First section of this Chapter gives a brief overview about OFDMA.OFDMA basically is the combination of Orthogonal Frequency Division Multiplexing (OFDM) and Frequency Division Multiplexing Access (FDMA).OFDMA provides high data rates even through multipath fading channels. In order to understand OFDMA, we must have brief introduction to Modulation, Multiple Access, Propagation mechanisms, its effects and its impairments while using OFDMA. 2.1 Modulation Modulation is the method of mapping data with change in carrier phase, amplitude, frequency or the combination [11]. There are two types of modulation techniques named as Single Carrier Modulation (SCM) Transmission Technique or Multicarrier Modulation (MCM) Transmission Technique. [12] Single Carrier Modulation (SCM) In single carrier transmission modulation (SCM) transmission, information is modulated using adjustment of frequency, phase and amplitude of a single carrier [12]. Multi Carrier Modulation (MCM) In multicarrier modulation transmission, input bit stream is split into several parallel bit streams then each bit stream simultaneously modulates with several sub-carriers (SCs) [12]. 2.2 Multiplexing Multiplexing is the method of sharing bandwidth and resources with other data channels. Multiplexing is sending multiple signals or streams of information on a carrier at the same time in the form of a single, complex signal and then recovering the separate signals at the receiving end [13]. 2.2.1 Analog Transmission In analog transmission, signals are multiplexed using frequency division multiplexing (FDM), in which the carrier bandwidth is divided into sub channels of different frequency widths,and each signal is carried at the same time in parallel. 2.2.2 Digital Transmission In digital transmission, signals are commonly multiplexed using time-division multiplexing (TDM), in which the multiple signals are carried over the same channel in alternating time slots. 2.2.3 Need for OFDMA General wireless cellular systems are multi-users systems. We have limited radio resources as limited bandwidth and limited number of channels. The radio resources must be shared among multiple users. So OFDM is a better choice in this case. OFDM is the combination of modulation and multiplexing. It may be a modulation technique if we analyze the relation between input and output signals. It may be a multiplexing technique if we analyze the output signal which is the linear sum of modulated signal. In OFDM the signal is firstly split into sub channels, modulated and then re-multiplexed to create OFDM carrier. The spacing between carriers is such that they are orthogonal to one another. Therefore there is no need of guard band between carriers. In this way we are saving the bandwidth and utilizing our resources efficiently. 2.3 Radio Propagation Mechanisms There are 3 propagation mechanisms: Reflection, Diffraction and Scattering. These 3 phenomenon cause distortion in radio signal which give rise to propagation losses and fading in signals [14]. 2.3.1 Reflection Reflection occurs when a propagating Electro-Magnetic (EM) wave impinges upon an object which has very large dimensions as compared to the wavelength of the propagating wave. Reflections occur from the surface of the earth and from buildings and walls. 2.3.2 Diffraction When the radio path between the transmitter and receiver is obstructed by a surface that has sharp irregularities (edges), diffraction occurs. The secondary waves resulting from the obstructing surface are present throughout the space and even behind the obstacle, giving rise to a bending of waves around the obstacle, even when a line-of-sight path does not exist between transmitter and receiver. At high frequencies, diffraction, like reflection, depends on the geometry of the object, as well as the amplitude, phase and polarization of the incident wave at the point of diffraction. 2.3.3 Scattering When the medium through which the wave travels consists of objects with dimensions that are small compared to the wavelength, and where the number of obstacles per unit volume is large. Scattered waves are produced by rough surfaces, small objects or by other irregularities in the channel. In practice, foliage, street signs and lamp posts produce scattering in a mobile radio communications system. 2.4 Effects of Radio Propagation Mechanisms The three basic propagation mechanisms namely reflection, diffraction and scattering as we have explained above affect on the signal as it passes through the channel. These three radio propagation phenomena can usually be distinguished as large-scale path loss, shadowing and multipath fading [14][15]. 2.4.1 Path Loss Path Lossis the attenuation occurring by an electromagnetic wave in transit from a transmitter to a receiver in a telecommunication system. In simple words, it governs the deterministic attenuation power depending only upon the distance between two communicating entities. It is considered as large scale fading because it does not change rapidly. 2.4.2 Shadowing Shadowingis the result of movement of transmitter, receiver or any channel component referred to as (obstacles). Shadowing is a statistical parameter. Shadowing follows a log-normal distribution about the values governed by path loss. Although shadowing depends heavily upon the channel conditions and density of obstacles in the channel, it is also normally considered a large scale fading component alongside path loss. 2.4.3 Multipath Fading Multipath Fadingis the result of multiple propagation paths which are created by reflection, diffraction and scattering. When channel has multiple paths. Each of the paths created due to these mechanisms may have its characteristic power, delay and phase. So receiver will be receiving a large number of replicas of initially transmitted signal at each instant of time. The summation of these signals at receiver may cause constructive or destructive interferences depending upon the delays and phases of multiple signals. Due to its fast characteristic nature, multipath fading is called small scale fading. 2.5 Orthogonal Frequency Division Multiplexing (OFDM) Orthogonal Frequency Division Multiplexing (OFDM) is an efficient multicarrier modulation that is robust to multi-path radio channel impairments [15]. Now-a-days it is widely accepted that OFDM is the most promising scheme in future high data-rate broadband wireless communication systems. OFDM is a special case of MCM transmission. In OFDM, high data rate input bit stream or data is first converted into several parallel bit stream, than each low rate bit stream is modulated with subcarrier. The several subcarriers are closely spaced. However being orthogonal they do not interfere with each other. 2.5.1 Orthognality Signals are orthogonal if they are mutually independent of each other. Orthogonality is a property that allows multiple information signals to be transmitted perfectly over a common channel and detected, without interference. Loss of orthogonality results in blurring between these information signals and degradation in communications. Many common multiplexing schemes are inherently orthogonal. The term OFDM has been reserved for a special form of FDM. The subcarriers in an OFDM signal are spaced as close as is theoretically possible while maintain orthogonality between them.In FDM there needs a guard band between channels to avoid interference between channels. The addition of guard band between channels greatly reduces the spectral efficiency. In OFDM, it was required to arrange sub carriers in such a way that the side band of each sub carrier overlap and signal is received without interference. The sub-carriers (SCs) must be orthogonal to each other, which eliminates the guard band and improves the spectral efficiency . 2.5.2 Conditions of orthogonality 2.5.2.1 Orthogonal Vectors Vectors A and B are two different vectors, they are said to be orthogonal if their dot product is zero 2.6 OFDM GENERATION AND RECEPTION OFDM signals are typically generated digitally due to the complexity of implementation in the analog domain. The transmission side is used to transmit digital data by mapping the subcarrier amplitude and phase. It then transforms this spectral representation of the data into the time domain using an Inverse Discrete Fourier Transform (IDFT) but due to much more computational efficiency in Inverse Fast Fourier Transform (IFFT), IFFT is used in all practical systems. The receiver side performs the reverse operations of the transmission side, mixing the RF signal to base band for processing, and then a Fast Fourier Transform (FFT) is employed to analyze the signal in the frequency domain. The demodulation of the frequency domain signal is then performed in order to obtain the transmitted digital data. The IFFT and the FFT are complementary function and the most suitable term depends on whether the signal is being recovered or transmitted but the cases where the signal is independent of this distinction then these terms can be used interchangeably [15]. 2.6.1 OFDM Block Diagram 2.6.2 Implementation of OFDM Block Diagram 2.6.2.1 Serial to Parallel Conversion: In an OFDM system, each channel can be broken down into number of sub-carriers. The use of sub-carriers can help to increase the spectral efficiency but requires additional processing by the transmitter and receiver which is necessary to convert a serial bit stream into several parallel bit streams to be divided among the individual carriers. This makes the processing faster as well as is used for mapping symbols on sub-carriers. 2.6.2.2 Modulation of Data: Once the bit stream has been divided among the individual sub-carriers by the use of serial to parallel converter, each sub-carrier is modulated using 16 QAM scheme as if it was an individual channel before all channels are combined back together and transmitted as a whole. 2.6.2.3 Inverse Fourier Transform: The role of the IFFT is to modulate each sub-channel onto the appropriate carrier thus after the required spectrum is worked out, an inverse Fourier transform is used to find the corresponding time domain waveform. 2.6.2.4 Parallel to Serial Conversion: Once the inverse Fourier transform has been done each symbol must be combined together and then transmitted as one signal. Thus, the parallel to serial conversion stage is the process of summing all sub-carriers and combining them into one signal 2.6.2.5 Channel: The OFDM signal is then transmitted over a channel with AWGN having SNR of 10 dB. 2.6.2.6 Receiver: The receiver basically does the reverse operations to the transmitter. The FFT of each symbol is taken to find the original transmitted spectrum. The phase angle of each transmission carrier is then evaluated and converted back to the data word by demodulating the received phase. The data words are then combined back to the same word size as the original data. 2.7 OFDMA in a broader perspective OFDM is a modulation scheme that allows digital data to be efficiently and reliably transmitted over a radio channel, even in multipath environments [17]. OFDM transmits data by using a large number of narrow bandwidth carriers. These carriers are regularly spaced in frequency, forming a block of spectrum. The frequency spacing and time synchronization of the carriers is chosen in such a way that the carriers are orthogonal, meaning that they do not interfere with each other. This is despite the carriers overlapping each other in the frequency domain [18]. The name ‘OFDM is derived from the fact that the digital data is sent using many carriers, each of a different frequency (Frequency Division Multiplexing) and these carriers are orthogonal to each other [19]. 2.7.1 History of OFDMA The origins of OFDM development started in the late 1950s with the introduction of Frequency Division Multiplexing (FDM) for data communications. In 1966 Chang patented the structure of OFDM and published the concept of using orthogonal overlapping multi-tone signals for data communications. In 1971 Weinstein introduced the idea of using a Discrete Fourier Transform (DFT) for Implementation of the generation and reception of OFDM signals, eliminating the requirement for banks of analog subcarrier oscillators. This presented an opportunity for an easy implementation of OFDM, especially with the use of Fast Fourier Transforms (FFT), which are an efficient implementation of the DFT. This suggested that the easiest implementation of OFDM is with the use of Digital Signal Processing (DSP), which can implement FFT algorithms. It is only recently that the advances in integrated circuit technology have made the implementation of OFDM cost effective. The reliance on DSP prevented the wide spread use of OFDM during the early development of OFDM. It wasnt until the late 1980s that work began on the development of OFDM for commercial use, with the introduction of the Digital Audio Broadcasting (DAB) system. 2.7.2 Advantages using OFDMA There are some advantages using OFDMA. OFDM is a highly bandwidth efficient scheme because different sub-carriers are orthogonal but they are overlapping. Flexible and can be made adaptive; different modulation schemes for subcarriers, bit loading, adaptable bandwidth/data rates possible. Has excellent ICI performance because of addition of cyclic prefix. In OFDM equalization is performed in frequency domain which becomes very easy as compared to the time domain equalization. Very good at mitigating the effects of delay spread. Due to the use of many sub-carriers, the symbol duration on the sub-carriers is increased, relative to delay spread. ISI is avoided through the use of guard interval. Resistant to frequency selective fading as compared to single carrier system. Used for high data rate transmission. OFDMA provides flexibility of deployment across a variety of frequency bands with little need for modification is of paramount importance. A single frequency network can be used to provide excellent coverage and good frequency re-use. OFDMA offers frequency diversity by spreading the carriers all over the used spectrum. 2.7.3 Challenges using OFDMA These are the difficulties we have to face while using OFDMA [20][21][22], The OFDM signal suffers from a very high peak to average power ratio (PAPR) therefore it requires transmitter RF power amplifiers to be sufficiently linear in the range of high input power. Sensitive to carrier frequency offset, needs frequency offset correction in the receiver. Sensitive to oscillator phase noise, clean and stable oscillator required. The use of guard interval to mitigate ISI affects the bandwidth efficiency. OFDM is sensitive to Doppler shift frequency errors offset the receiver and if not corrected the orthogonality between the carriers is degraded. If only a few carriers are assigned to each user the resistance to selective fading will be degraded or lost. It has a relatively high sensitivity to frequency offsets as this degrades the orthogonality between the carriers. It is sensitive to phase noise on the oscillators as this degrades the orthogonaility between the carriers. 2.7.4 Comparison with CDMA in terms of benefits 2.7.4.2 CDMA Advantages: CDMA has some advantages over OFDMA [22], Not as complicated to implement as OFDM based systems. As CDMA has a wide bandwidth, it is difficult to equalise the overall spectrum significant levels of processing would be needed for this as it consists of a continuous signal and not discrete carriers. Not as easy to aggregate spectrum as for OFDM. 2.7.5 OFDMA in the Real World: UMTS, the European standard for the 3G cellular mobile communications, and IEEE 802.16, a broadband wireless access standard for metropolitan area networks (MAN), are two live examples for industrial support of OFDMA. Table 1 shows the basic parameters of these two systems. Table 1. OFDMA system parameters in the UMTS and IEEE 802.16 standards 2.8 Radio Resource Management In second section of this chapter we will discuss radio resource management schemes, why we need them and how they improve the efficiency of the network. Radio resource management is the system level control of co-channel interference and other radio transmission characteristics in wireless communication systems. Radio resource management involves algorithms and strategies for controlling parameters such as Transmit power Sub carrier allocation Data rates Handover criteria Modulation scheme Error coding scheme, etc 2.8.1 Study of Radio Resource Management End-to-end reconfigurability has a strong impact on all aspects of the system, ranging from the terminal, to the air interface, up to the network side. Future network architectures must be flexible enough to support scalability as well as reconfigurable network elements, in order to provide the best possible resource management solutions in hand with cost effective network deployment. The ultimate aim is to increase spectrum efficiency through the use of more flexible spectrum allocation and radio resource management schemes, although suitable load balancing mechanisms are also desirable to maximize system capacity, to optimize QoS provision, and to increase spectrum efficiency. Once in place, mobile users will benefit from this by being able to access required services when and where needed, at an affordable cost. From an engineering point of view, the best possible solution can only be achieved when elements of the radio network are properly configured and suitable radio resource m anagement approaches/algorithms are applied. In other words, the efficient management of the whole reconfiguration decision process is necessary, in order to exploit the advantages provided by reconfigurability. For this purpose, future mobile radio networks must meet the challenge of providing higher quality of service through supporting increased mobility and throughput of multimedia services, even considering scarcity of spectrum resources. Although the size of frequency spectrum physically limits the capacity of radio networks, effective solutions to increase spectrum efficiency can optimize usage of available capacity. Through inspecting the needs of relevant participants in a mobile communication system, i.e., the Terminal, User, Service and Network, effective solutions can be used to define the communication configuration between the Terminal and Network, dependent on the requirements of Services demanded by Users. In other words, it is necessary to identify proper communications mechanisms between communications apparatus, based on the characteristics of users and their services. This raises further questions about how to manage traffic in heterogeneous networks in an efficient way. 2.8.2 Methods of RRM 2.8.2.1 Network based functions Admission control (AC) Load control (LC) Packet scheduler (PS) Resource Manager (RM) Admission control In the decision procedure AC will use threshold form network planning and from Interference measurements. The new connection should not impact the planned coverage and quality of existing Connections. (During the whole connection time.) AC estimates the UL and DL load increase which new connection would produce. AC uses load information from LC and PC. Load change depends on attributes of RAB: traffic and quality parameters. If UL or DL limit threshold is exceeded the RAB is not admitted. AC derives the transmitted bit rate, processing gain, Radio link initial quality parameters, target BER, BLER, Eb/No, SIR target. AC manages the bearer mapping The L1 parameters to be used during the call. AC initiates the forced call release, forced inter-frequency or intersystem handover. Load control Reason of load control Optimize the capacity of a cell and prevent overload The interference main resource criteria. LC measures continuously UL and DL interference. RRM acts based on the measurements and parameters from planning Preventive load control In normal conditions LC takes care that the network is not overloaded and remains Stable. Overload condition . LC is responsible for reducing the load and bringing the network back into operating area. Fast LC actions in BTS Lower SIR target for the uplink inner-loop PC. LC actions located in the RNC. Interact with PS and throttle back packet data traffic. Lower bit rates of RT users.(speech service or CS data). WCDMA interfrequency or GSM intersystem handover. Drop single calls in a controlled manner. 2.8.2.3 Connection based functions Handover Control (HC) Power Control (PC) Power control Uplink open loop power control. Downlink open loop power control. Power in downlink common channels. Uplink inner (closed) loop power control. Downlink inner (closed) loop power control. Outer loop power control. Power control in compressed mode. Handover Intersystem handover. Intrafrequency handover. Interfrequency handover. Intersystem handover. Hard handover (HHO). All the old radio links of an MS are released before the new radio links are established. Soft handover (SHO) SMS is simultaneously controlled by two or more cells belonging to different BTS of the same RNC or to different RNC. MS is controlled by at least two cells under one BTS. Mobile evaluated handover (MEHO) The UE mai Radio Resource Management in OFDMA Networks Radio Resource Management in OFDMA Networks 1 Introduction The convenience and popularity of wireless technology has now extended into multimedia communications, where it poses a unique challenge for transmitting high rate voice, image, and data signals simultaneously, synchronously, and virtually error-free. That challenge is currently being met through Orthogonal Frequency Division Multiplexing (OFDM), an interface protocol that divides incoming data streams into sub-streams with overlapping frequencies that can then be transmitted in parallel over orthogonal subcarriers [2,3]. To allow multiple accesses in OFDM , Orthogonal Frequency Division Multiple Access (OFDMA) was introduced. Relaying techniques, along with OFDMA, are used to achieve high data rate and high spectral efficiency. 1.1 Orthogonal Frequency Division Multiple Access OFDMA, an interface protocol combining features of OFDM and frequency division multiple access (FDMA)., was developed to move OFDM technology from a fixed-access wireless system to a true cellular system with mobility with same underlying technology, but more flexibility was defined in the operation of the system [1,8]. In OFDMA, subcarriers are grouped into larger units, referred to as sub-channels, and these sub-channels are further grouped into bursts which can be allocated to wireless users [4]. 1.2 Relay-Enhanced Networks In cellular systems, a way to achieve remarkable increase in data rate, but without claiming for more bandwidth, is to shrink cell sizes, however, with smaller cells more base stations (BSs) are needed to cover a same area due to which deployment and networking of new BSs acquire significant costs [5]. An alternative solution to this problem is to deploy smart relay stations (RSs), which can communication with each other and with BSs through wireless connections reducing systems cost. A relay station (RS), also called repeater or multi-hop station, is a radio system that helps to improve coverage and capacity of a base station (BS) and the resulting networks employing relay stations are sometimes called cooperative networks [6]. 1.3 Technological Requirement The continuously evolving wireless multimedia services push the telecommunication industries to set a very high data rate requirement for next generation mobile communication systems. As spectrum resource becomes very scarce and expensive, how to utilize this resource wisely to fulfil high quality user experiences is a very challenging research topic. Orthogonal frequency-division multiple access (OFDMA)-based RRM schemes together with relaying techniques allocate different portions of radio resources to different users in both the frequency and time domains and offers a promising technology for providing ubiquitous high-data-rate coverage with comparatively low cost than deploying multiple base stations [5]. Although wireless services are the demand of future due to their mobility and low cost infrastructure but along with this they suffer serious channel impairments. In particular, the channel suffers from frequency selective fading and distance dependent fading (i.e., large-scale fading) [1, 8]. While frequency selective fading results in inter-symbol-interference (ISI), large-scale fading attenuates the transmitted signal below a level at which it can be correctly decoded. Orthogonal Frequency-Division Multiple Access (OFDMA) relay-enhanced cellular network, the integration of multi-hop relaying with OFDMA infrastructure, has become one of the most promising solutions for next-generation wireless communications. 1.3.1 Frequency Selective Fading In wireless communications, the transmitted signal is typically reaching the receiver through multiple propagation paths (reflections from buildings, etc.), each having a different relative delay and amplitude. This is called multipath propagation and causes different parts of the transmitted signal spectrum to be attenuated differently, which is known as frequency-selective fading. In addition to this, due to the mobility of transmitter and/or receiver or some other time-varying characteristics of the transmission environment, the principal characteristics of the wireless channel change in time which results in time-varying fading of the received signal [9]. 1.3.2 Large Scale Fading Large scale fading is explained by the gradual loss of received signal power (since it propagates in all directions) with transmitter-receiver (T-R) separation distance. These phenomenonss cause attenuation in the signal and decrease in its power. To overcome this we use diversity and multi-hop relaying. 1.3.3 Diversity Diversity refers to a method for improving the reliability of a message signal by using two or morecommunication channelswith different characteristics. Diversity plays an important role in combatingfadingandco-channel interferenceand avoidingerror bursts. It is based on the fact that individual channels experience different levels of fading and interference. Multiple versions of the same signal may be transmitted and/or received and combined in the receiver [10]. 1.4 Proposed Simulation Model We developed a simulation model in which each user-pair is allocated dynamically a pair of relay and subcarrier in order to maximize its achievable sum-rate while satisfying the minimum rate requirement. The algorithm and the results of the simulation model are given in chapter 4. 1.5 Objectives The objective of our project is to have a detail overview of the literature regarding Orthogonal Frequency Division Multiple Access (OFDMA), Radio Resource Management (RRM) and Relaying techniques. After literature review we developed a simulation framework in which we will try to use minimum resources to get maximum throughput by using dynamic resource allocation. 1.6 Tools For the design and implementation of proposed Algorithm, we have used the following tools MATLAB Smart Draw Corel Draw 1.7 Overview Chapter 2 contains the literature review. It explains the basic principles of OFDMA, Radio Resource Management (RRM) and the relaying techniques. Chapter 3 explains the implementation of OFDM generation and reception that how an OFDM signal is generated and transmitted through the channel and how it is recovered at the receiver. Chapter 4 could be considered as the main part of thesis. It focuses on the simulation framework and the code. We have followed the paper â€Å"Subcarrier Allocation for multiuser two-way OFDMA Relay networks with Fairness Constraints†. In this section we have tried to implement the Dynamic Resource Allocation algorithm in order to achieve the maximum sum rate. Results are also discussed at the end of the end of the chapter. 2 Literature Review Introduction: First section of this Chapter gives a brief overview about OFDMA.OFDMA basically is the combination of Orthogonal Frequency Division Multiplexing (OFDM) and Frequency Division Multiplexing Access (FDMA).OFDMA provides high data rates even through multipath fading channels. In order to understand OFDMA, we must have brief introduction to Modulation, Multiple Access, Propagation mechanisms, its effects and its impairments while using OFDMA. 2.1 Modulation Modulation is the method of mapping data with change in carrier phase, amplitude, frequency or the combination [11]. There are two types of modulation techniques named as Single Carrier Modulation (SCM) Transmission Technique or Multicarrier Modulation (MCM) Transmission Technique. [12] Single Carrier Modulation (SCM) In single carrier transmission modulation (SCM) transmission, information is modulated using adjustment of frequency, phase and amplitude of a single carrier [12]. Multi Carrier Modulation (MCM) In multicarrier modulation transmission, input bit stream is split into several parallel bit streams then each bit stream simultaneously modulates with several sub-carriers (SCs) [12]. 2.2 Multiplexing Multiplexing is the method of sharing bandwidth and resources with other data channels. Multiplexing is sending multiple signals or streams of information on a carrier at the same time in the form of a single, complex signal and then recovering the separate signals at the receiving end [13]. 2.2.1 Analog Transmission In analog transmission, signals are multiplexed using frequency division multiplexing (FDM), in which the carrier bandwidth is divided into sub channels of different frequency widths,and each signal is carried at the same time in parallel. 2.2.2 Digital Transmission In digital transmission, signals are commonly multiplexed using time-division multiplexing (TDM), in which the multiple signals are carried over the same channel in alternating time slots. 2.2.3 Need for OFDMA General wireless cellular systems are multi-users systems. We have limited radio resources as limited bandwidth and limited number of channels. The radio resources must be shared among multiple users. So OFDM is a better choice in this case. OFDM is the combination of modulation and multiplexing. It may be a modulation technique if we analyze the relation between input and output signals. It may be a multiplexing technique if we analyze the output signal which is the linear sum of modulated signal. In OFDM the signal is firstly split into sub channels, modulated and then re-multiplexed to create OFDM carrier. The spacing between carriers is such that they are orthogonal to one another. Therefore there is no need of guard band between carriers. In this way we are saving the bandwidth and utilizing our resources efficiently. 2.3 Radio Propagation Mechanisms There are 3 propagation mechanisms: Reflection, Diffraction and Scattering. These 3 phenomenon cause distortion in radio signal which give rise to propagation losses and fading in signals [14]. 2.3.1 Reflection Reflection occurs when a propagating Electro-Magnetic (EM) wave impinges upon an object which has very large dimensions as compared to the wavelength of the propagating wave. Reflections occur from the surface of the earth and from buildings and walls. 2.3.2 Diffraction When the radio path between the transmitter and receiver is obstructed by a surface that has sharp irregularities (edges), diffraction occurs. The secondary waves resulting from the obstructing surface are present throughout the space and even behind the obstacle, giving rise to a bending of waves around the obstacle, even when a line-of-sight path does not exist between transmitter and receiver. At high frequencies, diffraction, like reflection, depends on the geometry of the object, as well as the amplitude, phase and polarization of the incident wave at the point of diffraction. 2.3.3 Scattering When the medium through which the wave travels consists of objects with dimensions that are small compared to the wavelength, and where the number of obstacles per unit volume is large. Scattered waves are produced by rough surfaces, small objects or by other irregularities in the channel. In practice, foliage, street signs and lamp posts produce scattering in a mobile radio communications system. 2.4 Effects of Radio Propagation Mechanisms The three basic propagation mechanisms namely reflection, diffraction and scattering as we have explained above affect on the signal as it passes through the channel. These three radio propagation phenomena can usually be distinguished as large-scale path loss, shadowing and multipath fading [14][15]. 2.4.1 Path Loss Path Lossis the attenuation occurring by an electromagnetic wave in transit from a transmitter to a receiver in a telecommunication system. In simple words, it governs the deterministic attenuation power depending only upon the distance between two communicating entities. It is considered as large scale fading because it does not change rapidly. 2.4.2 Shadowing Shadowingis the result of movement of transmitter, receiver or any channel component referred to as (obstacles). Shadowing is a statistical parameter. Shadowing follows a log-normal distribution about the values governed by path loss. Although shadowing depends heavily upon the channel conditions and density of obstacles in the channel, it is also normally considered a large scale fading component alongside path loss. 2.4.3 Multipath Fading Multipath Fadingis the result of multiple propagation paths which are created by reflection, diffraction and scattering. When channel has multiple paths. Each of the paths created due to these mechanisms may have its characteristic power, delay and phase. So receiver will be receiving a large number of replicas of initially transmitted signal at each instant of time. The summation of these signals at receiver may cause constructive or destructive interferences depending upon the delays and phases of multiple signals. Due to its fast characteristic nature, multipath fading is called small scale fading. 2.5 Orthogonal Frequency Division Multiplexing (OFDM) Orthogonal Frequency Division Multiplexing (OFDM) is an efficient multicarrier modulation that is robust to multi-path radio channel impairments [15]. Now-a-days it is widely accepted that OFDM is the most promising scheme in future high data-rate broadband wireless communication systems. OFDM is a special case of MCM transmission. In OFDM, high data rate input bit stream or data is first converted into several parallel bit stream, than each low rate bit stream is modulated with subcarrier. The several subcarriers are closely spaced. However being orthogonal they do not interfere with each other. 2.5.1 Orthognality Signals are orthogonal if they are mutually independent of each other. Orthogonality is a property that allows multiple information signals to be transmitted perfectly over a common channel and detected, without interference. Loss of orthogonality results in blurring between these information signals and degradation in communications. Many common multiplexing schemes are inherently orthogonal. The term OFDM has been reserved for a special form of FDM. The subcarriers in an OFDM signal are spaced as close as is theoretically possible while maintain orthogonality between them.In FDM there needs a guard band between channels to avoid interference between channels. The addition of guard band between channels greatly reduces the spectral efficiency. In OFDM, it was required to arrange sub carriers in such a way that the side band of each sub carrier overlap and signal is received without interference. The sub-carriers (SCs) must be orthogonal to each other, which eliminates the guard band and improves the spectral efficiency . 2.5.2 Conditions of orthogonality 2.5.2.1 Orthogonal Vectors Vectors A and B are two different vectors, they are said to be orthogonal if their dot product is zero 2.6 OFDM GENERATION AND RECEPTION OFDM signals are typically generated digitally due to the complexity of implementation in the analog domain. The transmission side is used to transmit digital data by mapping the subcarrier amplitude and phase. It then transforms this spectral representation of the data into the time domain using an Inverse Discrete Fourier Transform (IDFT) but due to much more computational efficiency in Inverse Fast Fourier Transform (IFFT), IFFT is used in all practical systems. The receiver side performs the reverse operations of the transmission side, mixing the RF signal to base band for processing, and then a Fast Fourier Transform (FFT) is employed to analyze the signal in the frequency domain. The demodulation of the frequency domain signal is then performed in order to obtain the transmitted digital data. The IFFT and the FFT are complementary function and the most suitable term depends on whether the signal is being recovered or transmitted but the cases where the signal is independent of this distinction then these terms can be used interchangeably [15]. 2.6.1 OFDM Block Diagram 2.6.2 Implementation of OFDM Block Diagram 2.6.2.1 Serial to Parallel Conversion: In an OFDM system, each channel can be broken down into number of sub-carriers. The use of sub-carriers can help to increase the spectral efficiency but requires additional processing by the transmitter and receiver which is necessary to convert a serial bit stream into several parallel bit streams to be divided among the individual carriers. This makes the processing faster as well as is used for mapping symbols on sub-carriers. 2.6.2.2 Modulation of Data: Once the bit stream has been divided among the individual sub-carriers by the use of serial to parallel converter, each sub-carrier is modulated using 16 QAM scheme as if it was an individual channel before all channels are combined back together and transmitted as a whole. 2.6.2.3 Inverse Fourier Transform: The role of the IFFT is to modulate each sub-channel onto the appropriate carrier thus after the required spectrum is worked out, an inverse Fourier transform is used to find the corresponding time domain waveform. 2.6.2.4 Parallel to Serial Conversion: Once the inverse Fourier transform has been done each symbol must be combined together and then transmitted as one signal. Thus, the parallel to serial conversion stage is the process of summing all sub-carriers and combining them into one signal 2.6.2.5 Channel: The OFDM signal is then transmitted over a channel with AWGN having SNR of 10 dB. 2.6.2.6 Receiver: The receiver basically does the reverse operations to the transmitter. The FFT of each symbol is taken to find the original transmitted spectrum. The phase angle of each transmission carrier is then evaluated and converted back to the data word by demodulating the received phase. The data words are then combined back to the same word size as the original data. 2.7 OFDMA in a broader perspective OFDM is a modulation scheme that allows digital data to be efficiently and reliably transmitted over a radio channel, even in multipath environments [17]. OFDM transmits data by using a large number of narrow bandwidth carriers. These carriers are regularly spaced in frequency, forming a block of spectrum. The frequency spacing and time synchronization of the carriers is chosen in such a way that the carriers are orthogonal, meaning that they do not interfere with each other. This is despite the carriers overlapping each other in the frequency domain [18]. The name ‘OFDM is derived from the fact that the digital data is sent using many carriers, each of a different frequency (Frequency Division Multiplexing) and these carriers are orthogonal to each other [19]. 2.7.1 History of OFDMA The origins of OFDM development started in the late 1950s with the introduction of Frequency Division Multiplexing (FDM) for data communications. In 1966 Chang patented the structure of OFDM and published the concept of using orthogonal overlapping multi-tone signals for data communications. In 1971 Weinstein introduced the idea of using a Discrete Fourier Transform (DFT) for Implementation of the generation and reception of OFDM signals, eliminating the requirement for banks of analog subcarrier oscillators. This presented an opportunity for an easy implementation of OFDM, especially with the use of Fast Fourier Transforms (FFT), which are an efficient implementation of the DFT. This suggested that the easiest implementation of OFDM is with the use of Digital Signal Processing (DSP), which can implement FFT algorithms. It is only recently that the advances in integrated circuit technology have made the implementation of OFDM cost effective. The reliance on DSP prevented the wide spread use of OFDM during the early development of OFDM. It wasnt until the late 1980s that work began on the development of OFDM for commercial use, with the introduction of the Digital Audio Broadcasting (DAB) system. 2.7.2 Advantages using OFDMA There are some advantages using OFDMA. OFDM is a highly bandwidth efficient scheme because different sub-carriers are orthogonal but they are overlapping. Flexible and can be made adaptive; different modulation schemes for subcarriers, bit loading, adaptable bandwidth/data rates possible. Has excellent ICI performance because of addition of cyclic prefix. In OFDM equalization is performed in frequency domain which becomes very easy as compared to the time domain equalization. Very good at mitigating the effects of delay spread. Due to the use of many sub-carriers, the symbol duration on the sub-carriers is increased, relative to delay spread. ISI is avoided through the use of guard interval. Resistant to frequency selective fading as compared to single carrier system. Used for high data rate transmission. OFDMA provides flexibility of deployment across a variety of frequency bands with little need for modification is of paramount importance. A single frequency network can be used to provide excellent coverage and good frequency re-use. OFDMA offers frequency diversity by spreading the carriers all over the used spectrum. 2.7.3 Challenges using OFDMA These are the difficulties we have to face while using OFDMA [20][21][22], The OFDM signal suffers from a very high peak to average power ratio (PAPR) therefore it requires transmitter RF power amplifiers to be sufficiently linear in the range of high input power. Sensitive to carrier frequency offset, needs frequency offset correction in the receiver. Sensitive to oscillator phase noise, clean and stable oscillator required. The use of guard interval to mitigate ISI affects the bandwidth efficiency. OFDM is sensitive to Doppler shift frequency errors offset the receiver and if not corrected the orthogonality between the carriers is degraded. If only a few carriers are assigned to each user the resistance to selective fading will be degraded or lost. It has a relatively high sensitivity to frequency offsets as this degrades the orthogonality between the carriers. It is sensitive to phase noise on the oscillators as this degrades the orthogonaility between the carriers. 2.7.4 Comparison with CDMA in terms of benefits 2.7.4.2 CDMA Advantages: CDMA has some advantages over OFDMA [22], Not as complicated to implement as OFDM based systems. As CDMA has a wide bandwidth, it is difficult to equalise the overall spectrum significant levels of processing would be needed for this as it consists of a continuous signal and not discrete carriers. Not as easy to aggregate spectrum as for OFDM. 2.7.5 OFDMA in the Real World: UMTS, the European standard for the 3G cellular mobile communications, and IEEE 802.16, a broadband wireless access standard for metropolitan area networks (MAN), are two live examples for industrial support of OFDMA. Table 1 shows the basic parameters of these two systems. Table 1. OFDMA system parameters in the UMTS and IEEE 802.16 standards 2.8 Radio Resource Management In second section of this chapter we will discuss radio resource management schemes, why we need them and how they improve the efficiency of the network. Radio resource management is the system level control of co-channel interference and other radio transmission characteristics in wireless communication systems. Radio resource management involves algorithms and strategies for controlling parameters such as Transmit power Sub carrier allocation Data rates Handover criteria Modulation scheme Error coding scheme, etc 2.8.1 Study of Radio Resource Management End-to-end reconfigurability has a strong impact on all aspects of the system, ranging from the terminal, to the air interface, up to the network side. Future network architectures must be flexible enough to support scalability as well as reconfigurable network elements, in order to provide the best possible resource management solutions in hand with cost effective network deployment. The ultimate aim is to increase spectrum efficiency through the use of more flexible spectrum allocation and radio resource management schemes, although suitable load balancing mechanisms are also desirable to maximize system capacity, to optimize QoS provision, and to increase spectrum efficiency. Once in place, mobile users will benefit from this by being able to access required services when and where needed, at an affordable cost. From an engineering point of view, the best possible solution can only be achieved when elements of the radio network are properly configured and suitable radio resource m anagement approaches/algorithms are applied. In other words, the efficient management of the whole reconfiguration decision process is necessary, in order to exploit the advantages provided by reconfigurability. For this purpose, future mobile radio networks must meet the challenge of providing higher quality of service through supporting increased mobility and throughput of multimedia services, even considering scarcity of spectrum resources. Although the size of frequency spectrum physically limits the capacity of radio networks, effective solutions to increase spectrum efficiency can optimize usage of available capacity. Through inspecting the needs of relevant participants in a mobile communication system, i.e., the Terminal, User, Service and Network, effective solutions can be used to define the communication configuration between the Terminal and Network, dependent on the requirements of Services demanded by Users. In other words, it is necessary to identify proper communications mechanisms between communications apparatus, based on the characteristics of users and their services. This raises further questions about how to manage traffic in heterogeneous networks in an efficient way. 2.8.2 Methods of RRM 2.8.2.1 Network based functions Admission control (AC) Load control (LC) Packet scheduler (PS) Resource Manager (RM) Admission control In the decision procedure AC will use threshold form network planning and from Interference measurements. The new connection should not impact the planned coverage and quality of existing Connections. (During the whole connection time.) AC estimates the UL and DL load increase which new connection would produce. AC uses load information from LC and PC. Load change depends on attributes of RAB: traffic and quality parameters. If UL or DL limit threshold is exceeded the RAB is not admitted. AC derives the transmitted bit rate, processing gain, Radio link initial quality parameters, target BER, BLER, Eb/No, SIR target. AC manages the bearer mapping The L1 parameters to be used during the call. AC initiates the forced call release, forced inter-frequency or intersystem handover. Load control Reason of load control Optimize the capacity of a cell and prevent overload The interference main resource criteria. LC measures continuously UL and DL interference. RRM acts based on the measurements and parameters from planning Preventive load control In normal conditions LC takes care that the network is not overloaded and remains Stable. Overload condition . LC is responsible for reducing the load and bringing the network back into operating area. Fast LC actions in BTS Lower SIR target for the uplink inner-loop PC. LC actions located in the RNC. Interact with PS and throttle back packet data traffic. Lower bit rates of RT users.(speech service or CS data). WCDMA interfrequency or GSM intersystem handover. Drop single calls in a controlled manner. 2.8.2.3 Connection based functions Handover Control (HC) Power Control (PC) Power control Uplink open loop power control. Downlink open loop power control. Power in downlink common channels. Uplink inner (closed) loop power control. Downlink inner (closed) loop power control. Outer loop power control. Power control in compressed mode. Handover Intersystem handover. Intrafrequency handover. Interfrequency handover. Intersystem handover. Hard handover (HHO). All the old radio links of an MS are released before the new radio links are established. Soft handover (SHO) SMS is simultaneously controlled by two or more cells belonging to different BTS of the same RNC or to different RNC. MS is controlled by at least two cells under one BTS. Mobile evaluated handover (MEHO) The UE mai

Essay example --

The goal of this experiment is to figure out the order of reaction for hydrogen peroxide and potassium iodide, and to determine the energy of activation. To do this experiment each solution is changed to different concentrations for each trial of the experiment; changing the concentration of KI and H2O2, will give the order of reaction. After finishing the experiment it found that the order of reaction was, rate= k[H2O2]2[KI]1, and the average rate constant k, was 4.8Â ·10-5. From the first and final experiment with a change in temperature, it was found that the energy of activation was .0002228152. The final results were that potassium iodide was a catalyst for the reaction and that its parts were close to the same after the reaction was over. Introduction H2O2 or hydrogen peroxide is an oxidizing agent that is used in many places like in sewage plants to destroy bacteria, and also in peoples homes and daily life as a disinfectant. Hydrogen Peroxide is stable, but it will slowly decompose over a long period of time. When put on an open cut, hydrogen peroxide has a very fast decomposition and O2 is developed. Again the same thing happens when the catalyst KI is used with H2O2. Because O2 is released as a product in the decomposition, a pressure verses time graph can be used to see the change in pressure. The pressure will change linearly to time first, but then after the initial short lag phase of stable pressure is over the pressure will begin to increase with time. In this experiment it’s crucial to record the rate of reactions because the kinetic order of reaction can be determined based off the differing concentration rates. The rates from the experiments will be measured in kPa/s and have to be converted to M/s by calcu... ...aq) + I-(aq) → IO-(aq) + H2O(aq). The result of this reaction is water and gas pressure because of the decomposition of the H2O2 by KI. The rate law is Rate=k[H2O2]2[KI]1 Conclusion This experiment has taught me how a catalyst actually works. I didn’t know that there were steps in between a catalyst in the reaction that were all used, and then replaced so the reaction is the same when its used and when it started the reaction again. I now have a far better understanding of how a catalyst speeds up a reaction by decreasing the reaction caused by the activation energy. I learned that a specific catalysts might work better at certain temperatures, and they can be measured by the different temperatures for the first reactions and the final reaction. I also learned that by measuring the rate constant at different temperatures, I can find the activation energy.

Liberal, Conservative, and Socialist Ideals vs. Feminism before the 20th Century :: Sociology Sociological Women Paperes

Liberal, Conservative, and Socialist Ideals vs. Feminism before the 20th Century Tales from the beyond, story one: a parent binds his baby girl's feet in China, so it will not grow more than five to six inches because small feet in women are a sign of elegance; story two: a wife is burned alive in India, so she can accompany her husband in death. Are these stories? No, things like this really happened in the past. They are part of the reason that contributed to the birth of the Women's Movement in the 19th century. This movement was also known as the Feminist movement because its foundation came from feminism, an ideology that developed in the 19th century, and whose main goal was to gain equality for women. The goals of the Women's Movement in the 19th century where: to get the vote, to archive equality in property rights, access to education, access to jobs and fair pay, divorce, and children's custody. These ideals had been around for a while, but the 19th century was the perfect time for them to develop. During the 19th century, nations were going throu gh radical changes; countries were adopting new ways of life based mainly of one of three ideologies: liberalism, conservatism, and socialism. The development of one of these ideologies, and the success of feminism in a country went hand in hand, and it is by analyzing the similarities, and differences between feminism, and each of these ideologies that we can see why feminism was most successful in liberal countries. Moral, political, and social are the three cores of liberalism, and the ideas in each core have a very similar resemblance to the ideas the feminist movement was trying to promote in the 19th century. Liberals believe that individuals had the right to personal liberties, which included the freedom to think, talk, and worship. Feminist believe women had the right to think, to have an opinion different from that of their husband, or fathers. The faith in total freedom, and equality for the individual that liberals, and feminist shared came from their faith in education. Their theory was that if individuals were educated, then they could be trusted to make the right decisions, decisions which would then in return helped make a better society. Adam Smith, writer of "The Wealth of Nations" considered the bible of liberal economics, believed in that theory, he expressed that "each person,.

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Cousin Kate is a poem about a young woman who is seduced by a Lord. He soon ensnares her and marries her cousin Kate instead, leaving behind a broken-hearted cottage maiden. The maiden is soon classed as a fallen woman and is treated like an outcast in society. She is bitter and jealous of her cousin but soon reveals that she has the one thing her cousin does not and desperately wants: a son and replacement to the Lord. The poem begins by saying ‘I was a cottage maiden’. It is a simple beginning, talking in the past tense. She tells us she is lower class person. It later says she is ‘Hardened by sun and air’ this shows that the cottage maiden is strong and worked outside on land and it also suggests by the use of the words â€Å"contented with my cottage mates† that she was happy and a sense of community . Then it says ‘why did a great lord find me out,’ this tells us that the lord has been chasing after her and she has been caught by him. In this stanza there is a question asked to the question reveals that the girl is puzzled about the lord is after her. This suggests that she is aware that he has different motives rather than love and romance. This also shows that she knows the compliment is false and just a way of seducing her into bed. The second stanza is where the great lord isn’t so â€Å"great† anymore. He lured and tricked her into going to his palace home. She then saw another life. Life without working and cleaning; however, the lord doesn’t take her seriously. He doesn’t feel like he has too as they are not married. â€Å"He wore me like a silken knot† is a simile which defines how he used her in his own way. He just wanted her as an accessory. â€Å"He changed me like a glove† this quote is also a simile which outlines h... ...fair haired son, my shame, my pride† We are told she has a son, and that not only is it a memory of her shame but he is her pride. He’s all she has. Then the last three lines on stanza six are switched. The narrator is now talking to her son, her pride. â€Å"Your father would give lands for one† she is telling her son that if his father really wanted to, he would take him and would leave her (the narrator) with nothing. In conclusion, â€Å"Cousin Kate† is an extremely complicated poem, and even though there’s hate and heartbreak throughout, she ends up with pride. The narrator let the lord control her, power over her and make her what he wanted; however, Cousin Kate didn’t. She would only let him have sex with her if she could still be pure; this means that she would have to be married to do so. This probably made the lord have massive respect for Kate and not the narrator.

Effects of Technology on Relationships

Yana Feldman Professor Ebersole Analytical Reading and Writing 0802 November 2, 2010 Advances in Communication and Intimate Relationships Instant digital and online communication of the modern world influences love and courtship in relationships. The generations of today allow their interpersonal relationships to be formed and shaped according to the technology that is offered. This is one of the many important matters that are influenced by technology. Technology is manipulating the world with positive and negative effects; it causes scientific advancement, it affects the economy, and importantly, it changes communication between people.This change can be seen in intimate relationships. To see how communication technology has changed love as a whole, one can observe how technology has changed different types, or stages, of intimate relationships. Three possible stages are an early dating stage at which flirting and courtship occur, a marital stage in which commitment is vital, and a long-distance relationship in which a couple is temporarily separated. These stages of relationships have changed in history and will continue to adjust according to society and, of course, technology. Communication has continuously been evolving ever since language existed.Language gives the distinctive ability for the evolution of human society. Language starts at the basis of spoken words; information is conveyed through conversation aloud or written in forms of letters. Efficient communication has involved written messages even in the earliest of civilizations. Since 522 BC written messages were sent between people in the Persian Empire. For a message to travel 2000 miles, it would take 10 days for a man on a horse at a speed of 200 miles per day; clearly, there were no other options or methods to send a message such a long distance.Until much more recent centuries, the only way to speed up the transferring of a message was to speed up the messenger himself. In the 11th century messages were sent slightly faster using pigeons (Gascoigne 1). As a next big step in the 15th century, the new technology of printing was invented. It spreads so quickly that every European country soon uses this new invention. The invention of the telescope in the 17th century allows for optical signals to be sent across a longer distance (Gascoigne 1).The application of electricity to enable communication did not come until much later in the form of the static electrical telegraph in the 18th century. Another long time passed post-telegraph telecommunications technologies before the speaking telephone would be invented (Winston 28). But by the time that Queen Victoria had ended her reign in 1901, the telegraph also left its greatest days behind (Standage 1). Distant signaling by voice appeared only 2 centuries ago—a very recent advancement considering how long communication has existed (Winston 33).The telephone was invented in the late 19th century—within 20 years , 2 million telephones existed in the United States. â€Å"During Queen Victoria’s reign, a new communications technology was developed that allowed people to communicate almost instantly across great distances, in effect shrinking the world faster and further than ever before. A worldwide communications network whose cables spanned continents and oceans, it revolutionized business practice, gave rise to new forms of crime, and inundated its users with a deluge of information. Romances blossomed over the wires† (Standage 1).Finally, the 20th century brought the inventions of the radio, television, and internet into human society; another influential invention was the famous cellular phones. These inventions spread to all parts of the world generously and quickly. With internet abilities, electronic mail became an option, and soon a preference over post mail. Instant messaging, text-messaging, and video chatting are all continuing to spread. Additionally, the convergenc e of internet and cellular devices can currently allow web access anytime and anywhere (â€Å"Internet† 1).The modern day communication options are incomparable to the early civilizations’ options. Modern communication capabilities cannot even be compared to the communication 200 years ago; so much has changed. Intimacy and loving relationships have always had certain steps and stages along the way. Dating and marriage are often regarded as popular topics of discussion. One can picture ladies gossiping and journalists commenting on what women should do, on what men should do, or how both parties should act in certain situations.However, love and intimacy are also sometimes observed in a more general and objective sense. The relationships of today can be compared with each other as well as compared to equal relationship settings of the past. Early developing intimate relationships today is a very open and general topic as compared to what it once used to be. â€Å"Cour tship no longer occupies a vital place in American culture. The term itself seems quaint and outdated† (Cere 4). Some researchers believe that the traditions of courtship eroded in the 20th century.They also believe that courtship’s end caused the destabilizing of marriage in recent years (Cere 4). Research shows that a device such as a cell phone and the text messaging that it offers substitutes face-to-face communication and is killing relationships. This is vital in an early developing relationship because communication in this stage can either cause the progress or downfall of the whole relationship. Interestingly, researchers have found that the reason men and women spend so much time on the Internet is because of the easy communication management and the environmental control that is offered.Particularly for the early stages of developing relationships, internet communication and other technological forms do not have any benefits (Kasallis). While research shows t hat text messages can be endearing and sweet for couples to interact and communicate, men and women may develop opposite opinions about the issue of text messaging. It seems that because text messaging (along with some other new technology) is so new, ground rules have not yet been established in the etiquette of the text message, and so for this reason these new technologies have had such pressure on early dating and flirting relationships (Pressner 1).In addition to the effects of text messaging and online communication to already developed intimate relationships, there is the whole issue of relationships that have been created in cyber ways. Social networks, such as Twitter and Facebook, offer the communication between old and new acquaintances. Yet today’s technology does not nearly end there; in addition to such online social locations for communication, couples and singles are offered with online dating services, such as Match. com and eHarmony.Such online services (now also accessible on cellular devices ever since the Cell and Internet convergence) are lacking reality and are artificial. Yet this does not stop men and women. In fact, the disconnectedness often attracts their attention and is tempting and addicting. Another stage of relationships is marriage. The marital stage is considered the most committed and based on emotional attachment. In this stage, the couple is considered dedicated and can be referred to as family members; the couple can also bear children. Research shows that marriage, partially due to the previous dating stage, has also changed in recent times.In the past, the â€Å"courtship† dating stage set clear ground for marriage as a next step. Since early dating is affected in modern day, marriage is not regarded as the next conceivable step. Also with technology changes, divorce laws have changed, allowing marriages to end with no faults, and opening more options to couples. â€Å"Many of the essential features of lo ve as courtship — the longing for permanence, the desire to donate the self to another — must, in the economists’ story of courtship, be either submerged into contract theory or dismissed altogether as irrational† (Cere 10).The effects of online communication and text messaging on marriage are observed as well; with both positive and negative effects. Noticeably, a little free time along with the internet is possibly harmful and damaging to a married couple. With services on the internet such as dating, social networks, and pornography, a dedicated husband or wife could get carried away. Such services are easily accessed, easy to use, and emotionally easy to handle because no work is required to be put in as with a husband or a wife.Nevertheless, other researchers say that marriage has been made easier in recent years due to the interconnectedness. A husband or wife can always send an email, make a phone call, or even easier—send a text message to o ne another. With this ability, there appears yet another aspect: married couples do not experience the love and desire for each other when not together (Sahlstein 1). A simple phone call can eliminate any feelings the couple has of missing one another or of desire for the other. With such quick digital communication today there is less of this excitement as in previous years.A third type of a relationship is a long-distance relationship. A simple example of such a couple is when the husband must leave for the military for long periods of time. In the internet age today, this long distance relationship is aided by such programs like Skype. A couple can not only send quick e-mails, it can talk on the phone, send instant messages, and video chat. This is somewhat of a revolution in comparison to relationships even a hundred years ago. Long distance relationships have had problems in all cultures and times.Since beginning of history, long distance relationships was a matter that was avo ided at all costs. Yet in today’s world, technology has definitely benefited this form of intimate relationship, allowing a couple to stay in touch in numerous ways. Most interestingly, studies show that in such a relationship, being together and being apart mutually allow and constrain on another in multiple ways (Sahlstein 1). Modern society is enhancing and providing this ability for long-distance romantic partners to feel connected and still be separated at the same time.The technology, particularly for communication enhancement, has changed probably the most in recent years causing changes and adjustments in all areas. Relationships and interpersonal communication is just one area that is currently affected, and it is not yet clear if it for the ultimate better or the eventual downfall of intimacy between men and women. In dating, marriage, and long-distance relationships, the effects of communication technology are currently observable. However, new technology is being developed and new standards are being set; and so, one may only wonder where intimate relationships will end up next. New problems may arise, as they always do in time; yet with such an instinctive and desired emotion of love, humans and their relationships will have the ability to prevail.Works Cited Cere, Dan. â€Å"The Experts’ Story of Courtship. † Institute for American Values. 2000. 01 November 2010. . Gascoigne, Bamber. â€Å"History of Communication† HistoryWorld. 2001. 01 November 2010. . Kasallis, Theresa. â€Å"Text messaging affects student relationships. † Universe. 5 Jul 2006. 01 November 2010. . Perlman, Daniel. Intimate Relationships. Toronto: McGraw-Hill Humanities Social, 2008. Pressner, Amanda. Can love blossom in a text message? † USA Today. 29 January 2006. 01 November 2010. . Sahlstein, Erin M. â€Å"Relating at a distance: Negotiating being together and being apart in long-distance relationships. † Journal of Social and Personal Relationships. 2010. 01 November 2010. . Standage, Tom. The Victorian Internet. New York: Walker Publishing, 2000. Winston, Brian. Media technology and society: a history: from the telegraph to the Internet. New York: Taylor and Francis e-Library, 2003. â€Å"Internet. † Encyclop? dia Britannica. 2010. Encyclop? dia Britannica Online. 01 Nov. 2010 .

A Critical Essay on Theodore Roethke’s “My Papa’s Waltz” Analysis

How can a poem written more than fifty years ago manage to find a more contemporary reading, and inspire a healthy yet critical discussion between ‘classicists’ and ‘modernist’ readers or audiences?Such is the charm exhibited by the poem My Papa’s Waltz written by Theodore Roethke. Even before jumping straight to the discussion of the meat and matter, or the content of the poem itself, there is already so much to say about the poem if we are to judge its literary merit in terms of form.NARRATIVE STRUCTURE, LANGUAGE AND RHYMEThe poem is very easily understood and is presented in a clear chronological order, from the time the father comes home, up to the conclusion of the ‘waltz’ with the speaker in the poem off to bed (Roethke).     Because of a clear chronology of events, the poem is light, delightful, and yet, remains thought-provoking.The language used is also very light and appropriate, as it is seen that the speaker in the poem is a child and the addressee is the papa, or the father of the speaker (Roethke). Such easy vocabulary is appropriate for the speaker in the poem, thus creating a high level of believability in the reader and lending credibility to the speaker in the poem.We see clearly and immediately the distinction between the speaker and the addressee, and we can also create in our minds the right profile for both speaker and addressee in the poem. The rhyme scheme is A-B-A-B-C-D-C-D-E-F-E-F-G-H-G-H.There is a wonderful mix of masculine rhymes; like head-bed in lines 13 and 15 (Roethke), and dirt-shirt in lines 14 and 16 (Roethke); and feminine rhymes like dizzy-easy in lines 1 and 3 (Roethke), and knuckle-buckle in lines 10 and 12 (Roethke) in the poem. The few ‘sloppy’ rhymes found in the poem are also interesting since they can be, again, attributed to the fact that the speaker is a person of tender age.IMAGERY AND FIGURATIVE LANGUAGEThe narrative structure of the poem is further b olstered by a clear and vivid rendering of images. The very first two lines – â€Å"The whiskey on your breath/Could make a small boy dizzy† (Roethke); – clearly and certainly presents a clear mental picture, where, not only the mind’s eye, but as well as other senses are able to participate: to be specific, in these lines, the sense of smell.Even the ‘mind’s ears’ are able to participate in the sensory experience of the poem as evidenced by lines 5 and 6 – â€Å"We romped until the pans/Slid from the kitchen shelf† (Roethke); where one could easily hear the racket that these pans sliding off kitchen shelves may have caused.This poem is simply a delight to the senses! The use of figurative language is superior as well. With lines 7 and 8 – â€Å"My mother's countenance/Could not unfrown itself† (Roethke), and the final lines – â€Å"Then waltzed me off to bed/ Still clinging to your shirt† (Roe thke) – are excellent and very inventive use of figurative language, not to mention it being far from clichà ©.The poem is a brilliant gem of literature that exhibits mastery, not only of poetic form, but as well as content. Speaking of content, this is exactly what has been subject of heated debates and lively discussion regarding the theme or the reading of the poem.DUALITY OF READINGThe poem presents a multilayered theme, capable of multiple readings. This conflict of reading and interpretation of the poems thematic or symbolic meaning stems from a difference in reader response to the poem.Most ‘classicists’ view the poem as an innocent and nostalgic retelling of a ‘bonding time’ between a doting father and a beloved son/child. On the other end of the spectrum are the ‘modernists’ interpretation of the poem as one which speaks of child abuse by physical punishment of a drunk father.The classicists argue that a reading of a poem shoul d also take into consideration the era or period at the time of the poem’s writing. They argue that the poem should not only be read and appreciated or criticized by using intrinsic information within the poem, but also extrinsic factors, such as the reference to line 1’s whiskey breath (Roethke), and lines 7 and 8’s mother’s countenance (Roethke).The modernists are in the view that this is not an enjoyable scenario for a child when such a dance is considered ‘not easy’ (Roethke) in line 4, as well as a ‘hung to death’(Roethke) in line3. Furthermore, violence is suggested by the hand holding on to the persona’s wrist in line 9, which is described as batter in one knuckle in line 10. There is also a strong suggestion of violence by the scrapping of the right ear in a buckle at every misstep (Roethke) in lines 11 and 12. Delivering the final nail to the coffin of the argument are the final lines 15 and 16’s waltzing o ff to bed still clinging to the abusive father’s shirt (Roethke), which shows reluctance and forcible tucking in of the speaker to the bed.I identify with the modernists in the reading and interpretation of this poem. I see violence and abuse in the poem, but to debate on such matters would be to entirely miss the point. The point here is that, this work is a marvelous piece of literature because it has the timeless quality of a classic, as well as a multi-faceted and multi-layered interpretation.After all, a good poem should impart a significant human experience, and it should draw from the reader, empathy, and a participation of the senses. Whether this is a nostalgic recall of good times between father and child or a violent episode of child abuse, the fact remains that the poem succeeds both in form and substance or content, and transcends time, is of essence. Its allowing for multiple readings is only a testament to the sterling qualities of this timeless classic.

JIT assessment

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